Development of new blood vessels and angiogenesis are initiated along with activation of endothelial cells of parental blood vessels. Growth factors that have been shown, in addition to the stimulation of such angiogenesis in vivo, to function mitogenically toward endothelial cells in vitro are termed “angiogenesis factor (angiogenesis growth factor)”.
The first therapeutic application of angiogenesis factor was reported by Folkman et al (N. Engl. J. Med. 285, 1182-1186 (1971)). According to later studies, the use of recombinant angiogenesis factors, such as the fibroblast growth factor (FGF) family (Science 257, 1401-1403 (1992); Nature 362, 844-846 (1993)), endothelial growth factor (EGF) (J. Surg. Res. 54, 575-583 (1993)), and vascular endothelial growth factor (VEGF), has been confirmed to promote and/or accelerate development of collateral circulatory tract in animal models of myocardial and hind limb ischemia (Circulation 90, II-228-II-234 (1994)). Furthermore, the present inventors discovered that hepatocyte growth factor (HGF), like VEGF, functions as an endothelium-specific growth factor (J. Hypertens. 14, 1067-1072 (1996)).
The strategy wherein angiogenesis factors are used for treating angiopathy (as mentioned above) is referred to as “angiogenic therapy.” Recently, extremely active research on angiogenic therapy is in progress for ischemic diseases and arterial diseases using genes of above-mentioned angiogenesis factors.
For example, the present inventors have elucidated the effectiveness of HGF genes against arteriosclerosis obliterans (ASO) (Circulation 100, No. 18, No. 1672 (1999); Japanese Circulation Journal 64 (Suppl.I), 478, No. P079 (2000)). Furthermore, it has been revealed that the HGF gene effectively functions against ischemic-reperfusion injury in myocardial infarction (Circulation 96, No. 8, No. 3459 (1997); Ann. Thorac. Surg. 67, 1726-1731 (1999); Gene Therapy, 7, 417-427 (2000)).
Furthermore, the effectiveness of the VEGF gene on swine myocardial ischemia model (Human Gene Therapy 10, 2953 (1999)) and rabbit hind limb ischemia model (Circulation 96 (suppl II): II-382-388 (1997)) has been established. In addition, the effect of VEGF on ASO patients (Circulation 97, 1114-1123 (1998)) and angina pectoris patients (Ann. Thorac. Surg. 68, 830-837 (1999)) has also been reported. Currently, in the U.S., clinical studies of VEGF gene therapy for ASO patients and angina pectoris patients are being carried out by groups such as Isner et al.
Regarding the bFGF gene, it has been reported that the number of blood vessels increase due to intramuscular introduction of the bFGF gene into a mdx mouse, a model for muscular dystrophy (Gene Therapy 6(7), 1210-1221 (1999)).
Prostacyclin (prostaglandin I.sub2; PGI.sub2), a kind of prostaglandin, is an unstable lipid mediator having a half-life of 5 to 10 minutes (Arch. Gynecol. Obstet. 243, 187-190 (1988)) It elucidates a strong vasodilating effect and platelet aggregation inhibitory effect through an increase of the cAMP levels mediated via G protein-coupled receptor (N. Engl. J. Med. 17, 1142-1147 (1979)). Currently, vasodilators, such as the PGI.sub2, PGE.sub1 (prostaglandin E.sub1) and derivatives thereof (analogues), are widely used for the therapy of various types of angiopathy. Specifically, expecting functions, such as vasodilatation and platelet aggregation inhibition, intra-arterial injection and intravenous injection of the PGE.sub1 are performed against peripheral hematogenic disorders (e.g., ASO and TAO (thromboangiitis obliterans)). Such injections have become is an established therapeutic method. Furthermore, since the PGI.sub2 has a strong effect and its inactivation occurs rapidly, various derivatives (iloprost, beraprost sodium, etc.) have been developed. These derivatives are used for the therapy of peripheral vascular occlusive disease and chronic arterial occlusion (Prostaglandins, Leukotrienes and Essential Fatty Acids. 54, 327-333 (1996); Yakugaku Zasshi, 117, 509-521 (1997)). Furthermore, PGE.sub1 and PGI.sub2 are used against peripheral circulatory dysfunction due to collagen disease, Raynaud's phenomenon, maintenance of extracorporeal circulation (Minerva Med. 89, 405-409 (1998)), heart failure (Am. Heart J. 134, 44-54 (1997)), and so on.
As mentioned above, substances, such as PGI.sub2, that have vasodilating effect and platelet aggregation inhibitory effect are known to be effective against various types of angiopathies. However, these substances have never been used in combination in the aforementioned angiogenic therapy with the HGF gene, and it has not been determined as to what kind of effects can be expected by such combination.
Furthermore, angiogenesis factors, such as HGF, VEGF, bFGF, and EGF, are know to enhance the expression of ets-1 (erythroblastosis virus oncogene homolog 1), a transcription regulatory factor, and activate various types of factors involved in angiogenesis via the ets-1 (J. Cell. Physiol., 169, 522-531 (1996); “HGF no Bunshi Igaku (Molecular Medicine of HGF)”, Medical Review, 179-185 (1998)) However, the ets-1 gene has never been used for angiogenic therapy and its effect completely unknown.